A carbon nanotube (hereinafter, referred as to ‘CNT’ is understood that it is a cylindrical carbon nanotube having a diameter of 3 to 150 nm, preferably 3 to 100 nm, and a length of several times, i.e., at least 100 times as long as its diameter. The tube is consisted of aligned carbon atom layers and has cores of different types. The carbon nanotube is also called as a carbon fibril or a hollow carbon fiber. The carbon nanotube disclosed in the present invention is industrially important in the production of composite because of the size and specific properties of the carbon nanotube. It has an essential additional possibility in an electronic application, an energy application, and an additional application.
The carbon nanotube is generally manufactured by an arc discharge, a laser ablation, a chemical vapor deposition, etc. However, the arc discharge and laser ablation are difficult to perform a bulk production, and also the over cost of arc production and purchase cost of laser apparatus are problem.
Furthermore, the chemical vapor deposition has problems in that a synthesize velocity is very slow and CNT particles that are synthesized are too small in the case of using a gas-phase dispersion catalyst and there is a limit to the bulk production of CNT because a space use efficiency inside the reactor is significantly reduced in the case of using a substrate-supported catalyst.
It has been disclosed that a rotary kiln way for producing CNT is performed by injecting a hydrocarbon-based reaction gas after injecting a catalyst into a reactor of rotating drum type and a method for using a fluidized bed reactor for synthesizing CNT is performed by forming the fluidized bed, in which a fluidized medium in a state of heating is flow, and then synthesizing CNT in the fluidized bed as a bulk production method of CNT.
However, the rotary kiln way and the method for using the fluidized bed reactor have a limit on productivity thereby having maximum 80% level of conversion rate of carbon source and a problem in that a large dose of carbon dioxide, and the like is emitted due to an incineration of waste gas.
At this time, the incineration is to dispose an un-reacted carbon source raw material gas, H2 produced from the reaction, and N2, Ar, and the like that are an inert gas injected for a processing stability by using a conventional discharge gas combustion column (Flare Stack) and an incinerator, and also in order to perform the incineration, the cost related to H2 and N2 should be also considered because an excess H2 should be injected in at least the same with the amount of hydrocarbon as much as hydrocarbon that is a component of carbon nanotube.
In addition, a capital investment due to a large-scale apparatus and more than 4 columns due to a non-continuous adsorption and desorption processing should be required in the case of a cryogenic distillation and PSA (pressure swing adsorption) that are a gas separation type used for producing N2 and H2 and a conventional petro-chemical processing. Furthermore, refrigeration equipments should be required for reducing a temperature to the temperature of liquefaction in the case of the cryogenic distillation. Accordingly, the reduction of operational costs and simplification of processing can be possible when H2 can be selectively removed without the capital investments of large-scale equipments as mentioned above.